Brush making



March 26, 1957 E. ROLKER BRUSH MAKING Filed April 8, 1952 FIG.I.

llllll INVENTOR United States Patent O 2,186,222 BRUSH MAKING Edwin Rolker, Baltimore, Md.; Gertrude H. Rolker, executrix of said Edwin Rolker, deceased Application April 8, 1952, Serial No. 281,185

6 Claims. (Cl. 15-193) This invention relates to brushes and methods of making them, and more particularly to chisel-end brushes and methods of making such brushes.

Although the invention in the broader aspects relates to brushes in general, the preferred embodiment to be described hereinbelow pertains particularly to brushes of the type composed of a body of bristles assembled in a manner suitable for use in painting or coating surfaces with materials of a more or less uid character. More particularly the present invention relates to chisel-end brushes, that is, brushes in which the free end of the bristle body tapers inwardly from each face to form a rounded, convex edge of reduced width.

In general, paint brushes are presently manufactured in a manner developed many years ago wherein a selected bunch of bristles of predetermined length are assembled in a metal tube, generally referred to as a ferrule, which is formed to determine the physical size and shape of the bristle-body of the brush. The butt-ends of the bristles are dipped in a suitable bonding material or cement, such as liquid rubber, and thereafter placed on a heated plate to cure the cement so that the butt-ends of the bristles are secured firmly together. The butt-end of the bristle body then is pushed into the ferrule until the bristlebody extends about half way into the ferrule. A handle then is positioned in the open end of the ferrule and the handle and bristle-body are secured to the ferrule by nails, rivets or suitable fastening devices. All of these operations are performed manually and, consequently, the manual labor involved constitutes a major portion of the cost of paint brushes manufactured in this manner. Obviously, it is desirable to develop a brush having a construction adaptable to be manufactured in accordance with present day mass production ideas, and thereby eliminate the above-mentioned, time-consuming and tedious manual operations.

An object of the invention is to provide new and irnproved brushes and methods of making them.

Another object of the invention is to provide new and improved chisel-end brushes and methods of making them.

A further object of the invention is to provide a paint brush having a bristle-supporting structure designed to produce a chisel-end on the bristle body of the brush from a minimum quantity of substantially uniform length bristles without trimming the free ends of the bristles.

An additional object of the invention is to provide a new and improved paint brush having a bristle body composed of a plurality of discrete layers of bristles supported at one end thereof so as to form a rounded edge on the free end of the bristle-body and methods of making such brushes.

Another additional object of the invention is to provide a new and improved paint brush having a bristlebody fabricated from bristle stock of a desired length into a desired average shape without the use of a ferrule in Order to vobtain a longeractive portion of bristle-body than that obtained for the same length bristle stock when a ferrulevis used to form theV bristle-body of the brush.

A brush embodying certain features of the invention i may include a bristle-supporting member formed of an uncured elastomeric compound so as to have a pluralityT of shoulders extending'longitudinally along the 'opposite sides thereof, a bristle-body formed of a plurality of discrete layers of bristles of predetermined average length and having their butt-ends positionedk against said shoulders and bonded to the member, one layer of 4bristles being provided for eachshoulder provided on the mem` ber, each of said layers having a thickness equal tothe combined thickness of at least two individual Vbristles'and a width equal to the Width of the shoulder on which 'it is positioned, said shoulders being arranged to align the butt-ends of the layers of bristles in such relative positions on the member that opposite ends of the bristle layers form a chisel-edge on the bristle-body, the butt-ends of thebristles engaging the member permeated with `an elastomeric cement before being positioned on the member, said member and cement permeating the ends of the bristles being simultaneously subjected' to heat and pr'es, sure to cure said member and cement into an integral unit, a cap positioned over the base so as to extend over the bonded ends of the outer layers of bristles, anda handle attached to the member.

A method of making brushes in accordance with certain features of the invention may include the steps of forming an uncured elastomeric compound into an elon-l gated bristle-supporting member having a threaded member embedded therein so that a portion of the threaded member extends beyond the upper surface of the member and having a plurality of pairs of opposed parallel surfaces, each of said pairs of parallel surfaces lying in different parallel planes with respect to the upper surface of the member, forming bristles of a predetermined average length into tightly packed layers, having a uniform thickness equal to the combined thickness of at least two individual bristles, applying a liquified elastomeric cement to the butt-ends of the bristles formed into said layers so that the cement fills the interstices between the ends of the bristles, positioning a layer of .such bristles on each of the parallel surfaces of the member to form a stratified bristle-body on the member,.said layers being arranged on the supporting member so that the ends of the bristles coated with said cement engage said parallel surfaces thereof, placing a cap over the supporting member, supplying suicient heat and pressure to the thus assembled supporting member and bristle-body to cure the elastomeric compound and the cement simultaneously into a tough elastic state, and securing a handle on the threaded member so that it presses firmly against the cap.

Other objects and advantages of the invention will become apparent from the following detailed description of a specific embodiment thereof, when read in conjunction with the appended drawings in which:

Fig. 1 is a side elevation of a paint brush embodying certain features of the invention and having portions thereof broken away to illustrate the internal construction thereof;

Fig. 2 is an enlarged vertical section taken along line` 2-2 of Fig. l;

Fig. 3 is an enlarged horizontal section taken along line 3-3 of Fig. 1; and i Fig. 4 is an isometric view of a portion of the brushhead shown in Fig. l.

Referring now to the drawings in which identical parts` are identified by like reference numerals throughout the` Patented Mar. 26, 1951,

various views, there is shown in Figs. 1 and 2 a paint brush embodying certain features of the invention and comprising a suitably shaped handle secured to a brushhead indicated generally at 11 by means of a screw-eye 12 embedded in the head 11 in such a position that its threaded portion projects upwardly from the brush-head 11 in order that the handle 10 may be threaded thereon as shown. A cup-shaped cap 13 ts snugly over the brush-head 11 and is held on the brush-head by the lower end of the handle. A bristle-body indicated generally at 15 includes a plurality of layers of bristles of a predetermined length and has the naturally thick or butt-ends of the bristles bonded together and to the head 11, thereby leaving the naturally llight or ag portion of the bristles *free for the eective or active end 16 of the brush. The bristle-body 15 is formed and secured to the head 11 in a manner hereinafter to be described, so that the free end 16 of the brush body 15 has a substantially U-shaped cross section, as seen in Fig. 2, which forms a narrow edge 17 extending across the width of the bristle-body 1S.

The handle 10 of the brush preferably is made of wood, and the central portion thereof is shaped to fit comfortably in the hand. Due to the unique construction of my paint brush, wherein the screw-eye 12 is rmly embedded in the head 11 for the purpose of securing the handle to the head, the base of the handle 10 need not have a width equal to the width of the bristle body 15 as is required in brushes made in accordance with present day methods of manufacturing brushes, but preferably is made from flat stock having a thickness substantially equal to the thickness of the head 11, and having a width sufficient to permit the handle to be shaped so that it may be easily held in the human hand. My type of brush handle, obviously, requires considerably less material for its manufacture, is far simpler to manufacture and, consequently, the manufacturing cost per handle is substantially reduced over the manufacturing cost of handles used in the types of paint brushes well-known in the art.

The brush-head 11, Figs. 2 and 3, preferably is made from an elastomeric compound such as rubber, or rubber-like synthetic compounds such as Duprene or neoprene (polymerized chloroprene) which undergo a change in chemical structure similar to vulcanization that occurs in rubber compounds when subjected to heat and pressure. Synthetic rubber-like compounds such as neoprene and Duprene are preferred because they are practically insoluble in paint solvents. The brush-head 11 also may be formed from thermosetting and thermoplastic compounds capable of withstanding contact with solvents used in paints, varnishes and the like without serious deterioration.

The present invention contemplates the formation of the brush-head 11 by placing a given quantity of an uncured or unvulcanized elastomeric compound in a suitable mold (not shown) designed to hold the head portion of the screw-eye 12 so that it is embedded in the molded compound as shown in Fig. 4. The mold is constructed in accordance with well-established principles of the art, so that the mold cavity forms shoulders 20-20 and 21-21 along the opposite sides of the brush-head 11 and a narrow ribv 22 at the base of the head. The shoulders 20-20 lie in a horizontal plane indicated by the 'line A-A, and the shoulders 21-21 lie in a horizontal plane indicated by the line B--B which is parallel to, but spaced a predetermined distance below the plane A-A Fig. 2. The side portions 23 and 24 that connect the shoulders 20-20 and 21-21 and the sides of the rib 2,2 of the brush-head preferably taper inwardly toward the center of the head. The physical size of the head and the number of shoulders provided thereon are determined by the width of the brush to be formed, and the required `thickness of the bristle-body, respectively.

i The bristle-body 15, Figs. 2 and 3, is composed of an inner layer of bristles of substantially uniform average length positioned on each side of the tapered rib 22 with the butt-ends of the bristles resting against the shoulders 21--21, and an outer layer of bristles 31 positioned on the surfaces 23 and 24 with the butt-ends of the bristles resting against the shoulders Ztl-20 as seen in Fig. 2. FThe rib 22 has its opposite ends rounded at 34 (Fig. 3) so that the adjacent ends of the inner bristle-layers Bail- 31) come together at these points and thereby close the ends of the bristle-body 15 of the brush. The inner bristle layers 3ft-3G have a thickness equa-l to the depth of the shoulders 21-21, and the opposite sides of the rib 22 taper inwardly to cause the free ends of the inner bristle layers to butt together so as to form the narrow bristle edge 17 across the width of the bristle body. The extent of the taper provided in the sides of the rib 22 is determined by the average length of the individual bristles of the bristle stock used for the reason that the taper is designed to cause the free ends of the bristles to butt together with suflicient force to form the narrow edge 17 along the free end of the bristle body layers Sil-3%. The layers 31-31 likewise have a thickness equal to the depth of the shoulders 20-2@ and the surfaces 23 and 24 taper inwardly to an extent sufficient to cause the outer bristle layers to lie snugly against the inner layers Sii-3b. The shoulder 20--20 and 21-21 preferably are of equal depth, which depth is designed to be equal to the combined thickness of at least two individual bristles of the layers in order that bristle stock may be formed and held in the layers 3,0 30 and 31-31 before the layers are assembled on the head 11 as described and shown.

The butt-end portions of the bristles of the inner and outer bristle layers are permeated with a liquid cement, preferably made of the same elastomeric compound as that of the head 11, and the layers are placed on the head in the manner described hereinabove while the cement is in a tacky state. The cap is placed over the head and the entire head and bristle body assembly is placed in a mold which is heated so as to simultaneously cure the brush-head and the cement applied to the bristle-ends, whereby the ends of the bristles are securely bonded to the brush-head as the brush-head is cured into a hard7 tough member. The cap 13 is designed to extend downwardly over the brush-head and cover the butt-end portions of the bristles of the outer bristle layers 31-31 and thereby protect the bristle-ends from injury that may result in the normal use of the brush. The cap also prevents the individual bristles of the outer layer of bristles from being pulled away from the head 11 and its surrounding bristles.

The above-described construction of the brush-head 11, cap 13 and bristle-body 15 completely eliminates the use of nails, rivets or the like to secure the bristle body 15 to the brush-head 11. Thus, the bristle strain normally encountered in using the brush is taken directly by the head 11 and cap 13 because the bristles are bonded to the head. The rib 22 extending between the inner layers S19-3i? forms a fluid reservoir 37 within the bristle-body 15 which will retain fluid by capillarity and will gradually feed the Huid to the bristles as required. Since the bristles in the layers Sil-30 and 31-31 are made from bristle stock of predetermined average length, the arrangement of the inner layers against the shoulders 21--21 and the outer layers against the shoulders 20-20 produces a chisel end on the free or effective end 16 of the bristle-body 15. The variations in the length of the individual bristles normally present in any given bunch of bristles of a predetermined average length helps to smooth out the ends of the layers into a substantially uniform rounded edge on the bristle-body 15.

The above-described paint brush is capable of being manufactured in accordance with mass production methods and apparatus that are not readily employed in the manufacture of the common type of brush now in use. In manufacturing a brush embodying the principal features of my invention, it is contemplatedY that the brush..

head 11 is formed by conventionalextruding yapparatus or conventional molding apparatus having a plurality of cavities for producing a suitable number of brush-headsl upon each operation of the dies of the apparatus. A pre-mixed elastomeric compound such as natural rubber, or synthetic rubber-like compounds such as neoprene or Duprene, preferably, is used to form the brush-head 11, and the brush-head is formed from such a compound while it is in a cold state to prevent vulcanization or curing, as the case may be, from taking place during the formation of the compound into the shape of the head as shown in Fig. l. It is further contemplated that the molding apparatus `is located at one end of a bristlefeeding and handling device (not shown) designed to automatically feed bristles from a supply of bristle stock of predetermined average length into bristle layers, like the bristle layers 30-30 and 31-31, layers having a thickness greater than the combined thickness of at least two individual bristles of the layers are thereafter suitably conveyed past a suitable device designed to apply a coating of a liquified elastomeric compound on the butt-end portions of the individual bristles of the layers. An operator positioned at one end of such an apparatus merely lifts the bristle layers from the apparatus and places them against the shoulders 21-21 and 20-20, in that order, to form the bristle-body 15. The cement-coated ends of the bristles are placed against the sides 23 and 24 and the sides of the rib 12 of the brush-head, whereby the tacky condition of the coating of elastomeric cement causes the ends of the bristles to adhere to each other and to the uncured brush-head 15. The cap 13 then is fitted over the head and the entire assembly including the cap 13, the head 11 and the bristle-body 15 are placed in a mold cavity. The mold is closed and heated to simultaneously cure and set the elastomeric coating on the ends of the bristles and the elastomeric compound formed into the head into a hard, tough substance. Asa result, the coating'on the bristles and the brush-head are fused or welded together and thereby form a strong homogenous member, whereby the bristle layers are secured firmly together and to the head. After the assembly of the head and the bristle-body is removed from the mold, the handle 10 is threaded on the exposed end of the screw-eye embedded in the head to complete the manufacture of the brush. The above-described brush construction is given solely for the purpose of exemplifying the preferred embodiment of my invention, it being understood that the various features of the brush may be modified or varied to suit manufacturing procedures without departing from the spirit and scope of my invention.

What is claimed is:

l. A brush which comprises a preformed elongated bristle-body supporting member made of an elastomeric compound and having a plurality of substantially rightangle shoulders extending horizontally in a step-like manner along each side thereof, said shoulders having a predetermined depth and predetermined height, a bristlebody composed of a plurality of preformed layers of bristles of uniform predetermined length bonded to the member so that the butt-ends of the layers of bristles abut said right-angle shoulders of the member, one layer of bristles being provided in the bristle-body for each right angle shoulder, said layers of bristles being equal in length and having a thickness equal to the horizontal depth of the bristle-aligning shoulders, said step-like arrangement of the shoulders serves to position the outermost layer of bristles with respect to at least one inner layer of bristles so as to form a rounded edge on the free end of the bristle body, each of said layers having an elastomeric cement bonding the butt-ends of the bristles of each layer together into layers before layers f are assembled on the right angle shoulders of the supporting member, said supporting member and cement being simultaneously cured into an integral unit to bond pound and having a plurality of substantially right angle shoulders extending horizontally in a step-like manner along each side thereof, said shoulders having a prede-r termined depth and predetermined height, a bristle-body composed of a plurality of preformed discrete layers of bristles of substantially uniform length and positioned on the member so that the butt-ends of the bristles in the layers of bristles abut said shoulders, one layer of bristles being provided in the bristle body for each right angle shoulder, each of said layers extending the full width of its corresponding shoulder and having a thickness equal to the depth of the shoulders, said shoulders being spaced apart vertically and indented with respect to each other to forman outer layer of bristles and at least one inner layer of bristles extending below the outer layer so as to form a rounded end on the free end of said bristle-body, each of said layers of bristle having an elastomeric cement bonding the butt-end portions of the bristles of each layer together into layers of bristles before assembly of the layers on the right angle shoulders, said supporting member and cement being simultaneously cured into an integral unit to bond a uniform portion:

mined transverse depth such that the combined depth of the shoulders is less than the total depth of the member, a bristle-body composed of a plurality of preformed discrete layers of bristles of uniform length secured to the member so that the butt-ends of the bristles of the layers of bristles abut the right angle shoulders, one layer of bristles being positioned on each shoulder, said layers having a thickness equal to the transverse depth of the shoulders, said step-like arrangement of the shoulders along the opposite sides of the member forms an outer layer of bristles on each side of the bristle body with respect to at least one inner layer of bristles on each side of -the bristle body so as to form a rounded end `on the free end of the bristle-body, each of said layers having an elastomeric cement applied to the interstices of butt-end portions of the bristles together into layers before said layers are assembled on the member, said suppor-ting member and cement being simultaneously cured into an integral mass and thereby bond a uniform portion of the butt-ends of the bristles firmly together and to the member, a rigid cup-shaped cap fitted neatly over the supporting member so as -to cover the butt-ends of the outer layers of bristles, and a handle secured directly to the supporting member of the brush.

4. A brush which comprises a preformed elongated bristle-supporting member made of an elastomeric compound and having a plurality of substantially right angle shoulders ex-tending horizontally in a step-like manner along each side thereof, said shoulders having a uniform transverse depth such that the combined depth of the shoulders is less than the total depth lof the member, a bristle-body composed of a plurality of preformed discrete layers of uniform length extending downwardly from said member and positioned on the member so that the butt-ends of the bristles engage the right angle shoulders, one layer of bristles being provided in the bristle body for each right angle shoulder, each of said preformed layers of bristles having a -thickness equal to the depth of its corresponding shoulder' and having the butt-ends of the bristles `of each layer bonded together with an elastomeric cement to hold the bristles in layers for assembly on the member, said step-like arrangement of the shoulders forms an outer layer of bristles in the body and at least oneinner layer of bristles in the body in such a manner that the free end of the inner layer extends below the free end of the outer iayer to a substantially` chisel-shaped end on the free end-of the bristle-body, said member having the downwardly projecting sides of the shoulders tapering inwardly so as to cause the free end of the inner layer of bristles to engage each other and the free ends of the outer layers to press rmly against the adjacent inner layers of bristles, a cup-shaped cap tted neatly over the member to cover the butt-ends of the outer layers of bristles, said member and cement being cured simultaneously with the cap positioned over the member to cure the member and the cement into an integral unit and thereby bond a predetermined portion or" the butt-ends of the bristles firmly together and to the member, handle fastening means embedded in the member and having a portion thereof projecting upwardly from the upper surface of the member, and a handle secured on the projecting portion of the handle-fastening means so as to press iirmly against the cap positioned on the supporting member.

5, The method of making brushes which comprises forming an uncured elastomeric compound into an elongated bristle-supporting member having a plurality of right angle shoulders extending horizontally in step-like manner along each side thereof, placing on each shoulder a preformed layer of bristles of substantially uniform length and having the butt-end portions of the bristles bonded together with an elastomeric cement, said cement being sufficiently tacky to cause the butt-end portions of the bristle layers to adhere to shoulders of the member and form a bristle-body on the member having a discrete inner layer of bristles and a discrete outer layer of u bristles, said step-like shoulders causing the free ends of the inner layers of bristles to extend beyond the free end of the outer layers by an amount sufficient to produce a substantially rounded edge on the free end of the bristlebody, heating the uncured member and the cement to cure them simultaneously into an integral mass and thereby bond the butt-ends of the bristles firmly together and to the member, and securing a handle to the member.

` 6. The method of making brushes which comp-rises forming an uncured eiastornerie compound into an elongated member having a handle receiving means embedded therein and having a plurality of right angle shoulders extending horizontally in a step-like manner along each side thereof, placing on each shoulder apreformed layer of bristles having a thickness equal to the depth of the shoulders and the butt-end portions of the bristles bonded together with an elastomeric cement so that the cemented ends of the bristles engage the shoulders and form a bristle-body on the member having an inner layer of bristles and an outer layer of bristles, said step-like arrangement of the shoulders causing the free end of 'the inner layer to extend below the free end of the outer layer so as to form a rounded edge on the free end of the bristle body, subjecting the member and the cement coating on the bristle ends to suicient heat and pressure to cure the member and the cement simultaneously into an integral mass and thereby bond the ends of the bristles rmly together and to Ithe member, and securing a handle to the handle receiving means imbedded in the member.

References Cited in the le of this patent UNiTED STATES PATENTS 878,344 Chazel Feb. 4, 1908 1,582,982 Grumbacher May 4, 1926 1,948,429 Robinson Feb. 20, 1934 2,258,361 Hewes Oct. 7, 1941 FOREIGN PATENTS 934,491 France Jan. 19, 1948 

